1. Field of the Invention
The invention relates to an axisymmetric, converging-diverging, axisymmetric turbojet-engine exhaust nozzle having a swiveling diverging component.
2. Description of the Related Art
More specifically the invention relates to a converging-diverging, axisymmetric turbojet-engine exhaust nozzle which, downstream of an exhaust duct having an axis X, there is provided a first ring of converging flaps hinged on the downstream end of the exhaust duct and driven by first control means, and, downstream of the first ring of flaps, a second ring of diverging flaps is provided, the upstream ends of which are hinged on the downstream ends of the corresponding converging flaps and further, wherein the downstream ends of the second ring of flaps are linked by linkrods to a pivoting ring cooperating with a spherical segment of a fixed structure, said pivoting ring being driven by a second control means to deflect the jet of exhaust gases.
These axisymmetric swiveling nozzles impart additional agility to combat aircraft, and improved manoeuverability in pitch and yaw.
U. S.Pat. Nos. 5,150,839 and 5,511,376 disclose nozzles within which spherical walls are fixed relative to the exhaust duct.
In U.S. Pat. No. 5,150,839 a pivoting ring is situated inside a spherical wall and is kept against the inside of the spherical wall by the pressure which the jet of exhaust gases exerts on the diverging flaps.
In U.S. Pat. No. 5,511,376 a pivoting ring encloses a spherical segment and comprises an inner cylindrical surface allowing axial ring translation or its pivoting motion when driven by linear actuators.
The nozzle of the present invention may be characterized in that the pivoting ring swivels on the outer wall of a spherical segment to center said ring relative to the said spherical segment.
The invention furthermore comprises a rotation-blocking system preventing the ring from rotating around the nozzle control axis X. Advantageously this rotation-blocking system comprises at least one roller having a radial axis and borne on the pivoting ring such that it cooperates with the side walls of an aperture in the spherical segment and also such that it has an axis of symmetry corresponding with the axis X.
In order to allow varying of the exhaust cross-section of the ring of diverging flaps, the spherical segment advantageously is mounted on a fixed structure so as to be able to slide parallel to the axis X due to an axial displacement of the pivoting ring itself driven by the second control means. Preferably, the spherical segment is supported on a plurality of brackets affixed to the fixed structure and running parallel to the axis X. The spherical segment encloses said brackets and comprises a plurality of guide rollers cooperating with apertures in the brackets.